Method and apparatus for scrubbing gas

ABSTRACT

Gas to be scrubbed is conducted into an annular passage and through a rapidly rotating curtain of cleaning liquid provided across the passage by a rapidly rotating wheel issuing the liquid from radial jets, to entrap and thence drain out particulate matter from the gas.

Stts l lnl Arthur 11. Stone 106 Kings lltond Madison. NJ. 07940 747,310

July 24. W60

Aug. 3, 1971 lnventor AppLNo. Filed Patented METHOD AND APPARATUS FOR SCRUlBlBllNG GAS 11 Claims, 5 Drawing Fins.

U.S. Cl 2611/84, 261/88, 261/l 18. 55/230, 55/260 Int. Cl ..1B0ld 47/13 Field of Search i. 55/230, 260,4061261/88. 34, 84,85,90, 118

GAS

H9 1 i m-Q Primary Examiner-Tim R. Miles Assistant E.raminerSteven H. Markowitz Attorney-Frank Ledermann ABSTRACT: Gas to be scrubbed is conducted into an annular passage and through a rapidly rotating curtain of cleaning liquid provided across the passage by a rapidly rotating wheel issuing the liquid from radial jets, to entrap and thence drain out particulate matter from the gas.

LIQUID lhl Patented Aug. 121M 2 Sheets-Sheet 1 INVENTOR. ARTHUR F. STONE BY K} ATTURNEY Patented Aug. 3, 1971 2 Sheets-Sheet 2 A B F w INV/iN'lY/R. ARTHUR F. STONE ATTORNEY ME'IIIHIOI) ANID APPARATUS FOR @ClltlllllillllllNG GAS Various types of devices are known whose purpose it is to effect removal of particulate matter from gases prior to their exhaust into the atmosphere. The Johnstone et al. US. Pat. No. 2,604,185 utilizes a Venturi throat to obtain maximum velocity of the gas at the place where the cleaning liquid is admitted. The instant invention, instead of moving the gas to high velocity, moves the liquid to high velocity. Since the anticipated ratio of liquid to gas remains the same, a substantial saving in energy is also obtained.

It should not be necessary to repeat here a discussion of the size of droplets of atomized liquid required to collect the smallest size of particulate matter, for the above-mentioned Johnstone patent as well as other patents and publications sufficiently cover the subject. The instant invention is intended to do a thoroughly good and efficient job in scrubbing out of the gas all particulate matter including dust.

In the accompanying drawing, FIG. l is for the most part a central longitudinal section through an apparatus embodying features of the invention, and in part diagrammatic.

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1.

FIG. 3 is a fragmentary sectional view taken on the line 3-3 of FIG. l.

FIG. d is a fragmentary sectional view taken on the line 4-4 of FIG. 1, showing the liquid emitting wheel per se in side view, with parts broken away.

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 4.

Referring in detail to the drawing, the numeral designates a hollow housing circular in cross section having an inlet end and an outlet end 200. This housing is an outer housing coaxial within which and spaced radially therefrom is an inner housing II which is shown having conical ends 12 and 13. Thus an annular path or passage is provided through the housing 110 between the latter and the inner housing lll.

The inner housing 11 is formed of two mutually opposed parts 14 and 15, each of which might itself be termed a housing, having a circumferential gap 16 between them. The juxtaposed walls 17 and 18 of the parts 14 place l5, respectively, at the sides of the gap 16, are cylindrical and concentric with the corresponding cylindrical midportion 19 of the outer housing It).

The inner housing ll is shown supported from the outer housing by circumferentially spaced webs 2t and 29 whose primary function, however, is not to serve as supports as other support means, not shown, may be provided. The webs 28 are positioned on the side of the gap 16 facing the inlet end 20 and the webs 29 are positioned on the opposite side of the gap, facing the outlet end 20a. The webs 2h constitute partitions providing ducts in the said annular path and the webs 29 define ducts Alt), all of which will be further discussed below.

A wheel 21 whose outline only is shown in FIG. 1, in phantorn, is mounted in the plane of the gap 116 coaxially on the common axis of the housings l0 and ll. The diameter of the wheel is substantially equal to the diameter of the cylindrical portions l7, 18. The wheel has a relatively large number of equidistantly circumferentially spaced radial pipes or tubes 22 extending from a hollow hub 23 which is fed with water or other cleaning liquid by a pipe 2% led through suitable openings in the housings. Shown rather diagrammatically than structurally and merely as an example of a means for rapidly rotatingthe wheel, is a shaft 25 to turn the wheel, driven by a motor 26. Supports 2511 are shown for the shaft and supports 26a for the motor. To reduce or eliminate wind resistance of the rapidly rotating wheel it is provided on both sides with a frustoconical cover or shield within which the pipes 22 are enclosed.

The gas to be cleaned enters the inlet 20, generally under the influence of a blower, fan or other means, and is constrained by the housing or baffle 14 into the annular passage between the housings l0 and 11. With cleaning fluid fed into the wheel 21 while the wheel is rotating at high speed, for example 3600 rpm, it throws a rapidly rotating curtain of liquid completely across the annular path. With a wheel 12 inches in diameter, for example, rotating at 3600 r.p.m., the tangential velocity of the water emerging into the annular passage is about f.p.s. The impaction of the liquid and gas stream results in atomization of the liquid and ultimate particulate collection. The liquid containing the particulate matter is drained out of the device through a tangential drain 27 oriented to the rotational direction of the wheel. The cleaned or scrubbed gas continues on through the annular passage and through the outlet 20a. Preferably, since the scrubbed exiting gas will contain some mist, it is desirable to connect the outlet to a mist separator, not shown. Mist separators are well lcnown in the art, one example of such being disclosed in the Johnstone et al. patent.

It is to be noted that the webs 28 extend longitudinally for a distance from left to right, FIG. 3, and thence are deformed at an acute angle, shown merely by way of example as about 45 in the drawing, and that the webs 29 extend at a reverse angle of substantially the same amount. In general, the more acute the angle of the webs 2b is, within practical limits, the greater is the degree of impaction between liquid and gas.

The paths followed by the gas through the annular passage on either side of the curtain of liquid, are shown in FIG. 3 by horizontal arrows and by arrows which slope at about 45, while the direction of rotation of the wheel is shown by the arrow bearing the legend R. Thus, gas leaving the ducts 3t) impinges upon the curtain of liquid discharged by the wheel in a general direction counter to the direction of travel of the rotating wheel. This increases impaction to achieve increased atomization and resultant entrapment of the particulate matter by the liquid.

It is further to be noted that the exit ducts between the webs 29, through which the scrubbed gas and liquid pass, slope at an angle to the plane ofthe wheel in a general direction consonant with the direction of rotation of the wheel, that is, of the curtain of liquid, this facilitating the passage of the liquid and gas. The liquid which exits through the ducts $0 and contains trapped particulate matter, is thrown against the frustoconical wall 19a, the centrifugal action urging the liquid toward the drain 27.

As stated, gas entering at the inlet 20 is constrained to pass through the circumferential space between the periphery of the wheel 21 and the housing portion I19, so that the gas must get through the rotating curtain of liquid. For this purpose alone the ducts 30, It) need not be necessary. However, by directing the gas against the rotating curtain counter to the direction of travel of the curtain, in other words by directing the gas against the oncoming liquid stream, as is done by the ducts 30, the collision effect and consequent atomizing of the liquid are enhanced. And obviously by conducting the exiting liquid and gas in a direction aided by the direction of rotation of the curtain, as is done by the ducts 40, their passage is facilitated.

What I claim is as follows:

I. A method of scrubbing gas consisting in providing an annular passage and a rapidly rotating curtain of cleaning liquid across said passage in a plane normal to the axis of said passage, and forcing the gas to be scrubbed along said passage and through said curtain at an acute angle to said plane opposed to the direction of rotation of the curtain.

2. A method according to claim ll, consisting additionally in directing the scrubbed gas and liquid containing particulate matter exiting from said curtain at an acute angle to said plane in a direction consonant with the direction of rotation of the curtain.

3. Apparatus for scrubbing gas including a hollow outer housing circular in cross section having an inlet end and an outlet end, an inner housing shaped substantially into a cone mounted coaxially within and radially spaced from said outer housing with the apex of the cone facing toward said inlet end thereby constituting a baffle for conducting gas entering the inlet along an annular path between said outer housing and said baffle, said baffle having the circumferential edge thereof opposite said apex lying in a plane normal to the common axis of said bafl'le and said outer housing, a wheel having a diameter substantially equal to the diameter of said circumferential edge rotatably mounted on said axis, said wheel being positioned with the peripheral edge thereof closely adjacent said circumferential edge and having a plurality of circumferentially spaced radial pipes extending from the hub thereof, means for rotating said wheel, and means for feeding liquid into said hub and through said pipes, whereby upon rapid rotation of said wheel and simultaneous emission of liquid from said pipes a rapidly rotating curtain ofliquid extends across said path, said outer housing having a drain positioned between the plane of said wheel and said outlet end, said outer housing having a portion of the surface thereof on both sides of said plane cylindrical, said baffle having a portion of the surface thereof adjacent said circumferential edge thereof cylindrical, and a plurality of circumferentially spaced webs extending between said cylindrical portions thereby providing circumferentially spaced ducts in said annular path adjacent said curtain of liquid, said webs being inclined at an acute angle to said plane in a direction counter to the direction of rotation of said wheel.

4. Apparatus according to claim 3, having an additional cylindrical inner housing mounted coaxially with said baffle and having the same diameter as said cylindrical portion of the baffle, said additional inner housing being positioned with one circumferential edge thereof closely adjacent the periphery of said wheel on the side of the wheel opposite said baffle, and a plurality of additional circumferentially spaced webs extending between said cylindrical portion of said outer housing and said additional inner housing, said additional webs being inclined at an acute angle to said plane in a direction consonant with the direction of rotation of said wheel.

5. Apparatus according to claim 4, said additional inner housing having a substantially cone-shaped extension extending from the other circumferential edge thereof in a direction toward said outlet end of said outer housing. said 6. Apparatus according to claim 5, said inlet and outlet ends of said outer housing having smaller diameters than said cylindrical portion thereof, the walls of said outer housing between said cylindrical portion thereof and said inlet and outlet ends thereof being substantially frustoconical in conformation.

7. Apparatus according to claim 3, said wheel having an each side thereof a frustoconical shield covering said pipes.

8. Apparatus for scrubbing gas consisting of an outer housing substantially circular in cross section having an inlet end and an outlet end, a coaxial inner housing positioned within and radially spaced from said outer housing, each of said housings having a portion thereof spaced from the ends thereof cylindrical, the cylindrical portion of the inner housing being positioned radially inward from the cylindrical portion of the outer housing, said inner housing having a circumferential gap between the ends of said cylindrical portion thereof dividing the inner housing into two opposed parts, a first plurality of circumferentially spaced webs extending between said cylindrical portion of the outer housing and that part of the cylindrical portion of said inner housing which is on the side of said gap facing said inlet end, a second plurality of circumferentially spaced webs extending between said cylindrical portion of the outer housing and the cylindrical portion of the inner housing on the opposite side of said gap, the end of said inner housing which faces said inlet end being shaped substantially into a cone, a wheel rotatably mounted on the common axis of said housing, said wheel having a diameter substantially equal to the diameter of said cylindrical portion of the inner housing and being positioned in the plane of said gap, said wheel having a hollow hub and a plurality of circumferentially spaced radial pipes leading from said hub, means for feeding liquid into said hub and hence said pipes, and means for rotating said wheel, said first plurality of webs extending at an angle to said plane in a direction counter to the direction of rotation of said wheel, said outer housing having a drain positioned between said outlet end thereof and said gap.

9. Apparatus according to claim 8, said second plurality of webs extending at an angle to said plane consonant with said rotational direction of the wheel.

10. Apparatus according to claim 9, the end of said inner housing which faces said outlet end being shaped into a cone, the portions of said outer housing between said cylindrical portion thereof and said inlet and outlet ends being frustoconical in conformation.

11. Apparatus according to claim 10, said drain being positioned at the bottom of the outer housing adjacent the frustoconical portion thereof and being oriented to said rotational direction of said wheel. 

2. A method according to claim 1, consisting additionally in directing the scrubbed gas and liquid containing particulate matter exiting from said curtain at an acute angle to said plane in a direction consonant with the direction of rotation of the curtain.
 3. Apparatus for scrubbing gas including a hollow outer housing circular in cross section having an inlet end and an outlet end, an inner housing shaped substantially into a cone mounted coaxially within and radially spaced from said outer housing with the apex of the cone facing toward said inlet end thereby constituting a baffle for conducting gas entering the inlet along an annular path between said outer housing and said baffle, said baffle having the circumferential edge thereof opposite said apex lying in a plane normal to the common axis of said baffle and said outer housing, a wheel having a diameter substantially equal to the diameter of said circumferential edge rotatably mounted on said axis, said wheel being positioned with the peripheral edge thereof closely adjacent said circumferential edge and having a plurality of circumferentially spaced radial pipes extending from the hub thereof, means for rotating said wheel, and means for feeding liquid into said hub and through said pipes, whereby upon rapid rotation of said wheel and simultaneous emission of liquid from said pipes a rapidly rotating curtain of liquid extends across said path, said outer housing having a drain positioned between the plane of said wheel and said outlet end, said outer housing having a portion of the surface thereof on both sides of said plane cylindrical, said baffle having a portion of the surface thereof adjacent said circumferential edge thereof cylindrical, and a plurality of circumferentially spaced webs extending between said cylindrical portions thereby providing circumferentially spaced ducts in said annular path adjacent said curtain of liquid, said webs being inclined at an acute angle to said plane in a direction counter to the direction of rotation of said wheel.
 4. Apparatus according to claim 3, having an additional cylindrical inner housing mounted coaxially with said baffle and having the same diameter as said cylindrical portion of the baffle, said additional inner housing being positioned with one circumferential edge thereof closely adjacent the periphery of said wheel on the side of the wheel opposite said baffle, and a plurality of additional circumferentially spaced webs extending between said cylindrical portion of said outer housing and said additional inner housing, said additional webs being inclined at an acute angle to said plane in a direction consonant with the direction of rotation of said wheel.
 5. Apparatus according to claim 4, said additional inner housing having a substantially cone-shaped extension extending from the other circumferential edge thereof in a direction toward said outlet end of said outer housing. said
 6. Apparatus according to claim 5, said inlet and outlet ends of said outer housing having smaller diameters than said cylindrical portion thereof, the walls of said outer housing between said cylindrical portion thereof and said inlet and outlet ends thereof being substantially frustoconical in conformation.
 7. Apparatus according to claim 3, said wheel having an each side thereof a frustoconical shield covering said pipes.
 8. Apparatus for scrubbing gas consisting of an outer housing substantially circular in cross section having an inlet end and an outlet end, a coaxial inner housing positioned within and radially spaced from said outer housing, each of said housings having a portion thereof spaced from the ends thereof cylindrical, the cylindrical portion of the inner housing being positioned radially inward from the cylindrical portion of the outer housing, said inner housing having a circumferential gap between the ends of said cylindrical portion thereof dividing the inner housing into two opposed parts, a first plurality of circumferentially spaced webs extending between said cylindrical portion of the outer housing and that part of the cylindrical portion of said inner housing which is on the side of said gap facing said inlet end, a second plurality of circumferentially spaced webs extending between said cylindrical portion of the outer housing and the cylindrical portion of the inner housing on the opposite side of said gap, the end of said inner housing which faces said inlet end being shaped substantially into a cone, a wheel rotatably mounted on the common axis of said housing, said wheel having a diameter substantially equal to the diameter of said cylindrical portion of the inner housing and being positioned in the plane of said gap, said wheel having a hollow hub and a plurality of circumferentially spaced radial pipes leading from said hub, means for feeding liquid into said hub and hence said pipes, and means for rotating said wheel, said first plurality of webs extending at an angle to said plane in a direction counter to the direction of rotation of said wheel, said outer housing having a drain positioned between said outlet end thereof and said gap.
 9. Apparatus according to claim 8, said second plurality of webs extending at an angle to said plane consonant with said rotational direction of the wheel.
 10. Apparatus according to claim 9, the end of said inner housing which faces said outlet end being shaped into a cone, the portions of said outer housing between said cylindrical portion thereof and said inlet and outlet ends being frustoconical in conformation.
 11. Apparatus according to claim 10, said drain being positioned at the bottom of the outer housing adjacent the frustoconical portion thereof and being oriented to said rotational direction of said wheel. 